On Saturday morning, Nickelodeon will take the lid off a slicker, hipper version of "Teenage Mutant Ninja Turtles." The armed reptiles, a hugely popular cartoon franchise in the '80s and '90s, are the latest effort by the children's network to combat a dramatic ratings plunge.

Over the past year, Nickelodeon has lost 28% of its young audience, according to ratings firm Nielsen. The network's signature programming, "SpongeBob SquarePants" and tween sensation "iCarly," have lost cache with kids who are turning to other channels and other entertainment such as video games.